The present invention relates generally to the field of expansion joints for building structures such as, e.g. floors, ceilings and walls. The present invention relates more specifically to a joint cover which is biased against the structure surfaces adjacent to an expansion gap within the respective floor, ceiling or wall. The biasing force is preferably generated by a spring assembly including a spring retained by a spring retainer which provides for adjustability of the spring force, as well as simplified assembly and removal with respective to the other components forming the expansion joint assembly.